“Whammo,we got caught with our pants down,” a CIA analyst says of the Tet Offensive, the massive surprise attack that North Vietnam launched against American and South Vietnamese forces in the pre-dawn hours of January 31st, 1968. Just what exactly happened and what it signified would take some time to sort out, but the message from Hanoi to the White House was immediate and unmistakeable: We will outlast you. In this final episode of the series: Tet '68 and its transformative impact on American understanding of the war.